Fluid pumps



Dec. l, 19704 D. F. MowBRAY FLUID PUMPS Filed Oct. 4, 1968 ATTORNEYS United States Patent O 3,544,245 FLUID PUMPS Dorian Farrar Mowbray, Burnham, England, assignor t C.A.V. Limited, Warply Way, Acton, London, a British company Filed Oct. 4, 1968, Ser. No. 765,067 Claims priority, application Great Britain, Oct. 9, 1967, 46,091/ 67 Int. Cl. F044: 1/00, 17/02; F02b 53/00 U.S. Cl. 418-258 5 Claims ABSTRACT OF THE DISCLOSURE A fluid pump in which a rotor is located within a pumping chamber and has its axis off-set `from the axis of the pumping chamber. A pair of blades is slidable within grooves formed in the rotor and each blade is divided into two overlapping-parts, with resilient means being provided to urge the ends of the two parts of the blades into engagement with the peripheral surface of the pumping chamber.

BACKGROUND `OF THE INVENTION This invention relates to iluid pumps of the kind comprising in combination, a pumping chamber having a substantially cylindrical internal peripheral surface and end walls, a rotor located in said pumping chamber, said rotor being rotatable about an axis olf-set from the axis of the pumping chamber, at least a pair of blades slidable within grooves formed in the rotor, the opposite ends of each blade co-operating with the peripheral surface of the pumping chamber and an inlet and an outlet port in communication with said chamber, and through which uid passes as the rotor rotates within the pumping chamber.

The object of the invention is to provide such a pump in a simple and convenient form.

SUMMARY OF THE INVENTION According to the invention in a pump of the kind specied, each blade is divided into two parts and resilient means is provided to urge the ends of the two parts of the blade into engagement with the peripheral surface of the pumping chamber.

In the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a sectional and inverted plan view of one example of a uid pump, taken on the line 1-1 of FIG. 2,

FIG. 2 is an end view in the direction of the arrow A of the pump shown in FIG. 1 with the end cover removed and FIG. 3 is a view in the direction of the arrow A of the end cover.

DETAILED DESCRIPTION `01"" THE INVENTION Referring to the drawings, there is provided a pump body in which is dened a substantially cylindrical pumping chamber having a peripheral boundary surface 11. End closure covers 12 and 13 are provided which constitute end Walls of the pumping chamber. Extending within the pumping chamber is a rotor 14 in which are formed diametrical slots or grooves 15 and 16, and the axis of rotation of the rotor is olf-set relative to the axis of the pumping chamber. Mounted within the slots respectively are a pair of blades 17 and 18 having cut away portions 20, intermediate their ends.

The blades 17, 18 are slidably mounted within the slots and as the rotor is rotated, the portions of the pumping chamber defined between adjacent blades increase and iCC reduce in volume. The pumping chamber is provided with an inlet port 21 and an outlet port 22 through which the fluid to be pumped is conveyed to and from the pumping chamber, -with these ports being formed in the end cover 12.

Conventionally, the blades are of one piece construction so that a running clearance must be provided between the tips of the blades and the peripheral surfacev of the pumping chamber and additionally, the width of the blades must be slightly less than the distance between the end walls of the pumping chamber for providing a running clearance. Unfortunately this clearance permits leakage to occur within the pump. In order to reduce the leakage, each blade is formed in two parts, with portions of the parts overlapping each other as is shown in FIG. 2. Moreover, each blade has a pair of leaf springs 19 which are provided to urge the parts of the blade outwardly relative to each other. In this manner the end surfaces of the blades are maintained in contact with the peripheral surface 11 of the pumping chamber.

In order to minimize the leakage which occurs between the blades and the end walls, it is arranged that the portions of each blade are urged axially in the opposite direction. This is achieved by inclining the surfaces against which the springs 19 act, relative to the axis of rotation of the rotor. Since each blade is provided with a pair of springs, the inclination of the surfaces on the portions of the blade are such that the two springs urge the parts of the blade in the correct direction. Moreover, in order to locate the springs against axial movement, one of the surfaces is provided with a depression in which the spring is accommodated. By this arrangement, the leakage path for the fuel is staggered and this elects an improvement in the performance of the pump. It will be noted that each spring is conlined by the adjacent face of the slot 16.

It will be appreciated that the peripheral surface of the pumping chamber when each blade is of one piece construction cannot be truly cylindrical, since the length of each blade cannot be greater than the distance measured between the opposite point of the peripheral surface in a plane at right angles to the plane containing the axis of the pumping chamber and the axis of rotation of the rotor, and the iirst mentioned plane also includes the axis of rotation of the rotor. With this length of blade and with a truly cylindrical pumping chamber, when the blades are at right angles to the first mentioned plane, there would be an appreciable gap between the ends of the blades and the peripheral surface so that the pump would be inoperative. The pumping chamber is therefore shaped accordingly.

When the blades are modilied as described, the pumping chamber may retain its original shape (as is shown) or it can be made truly cylindrical.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A uid pump comprising a body provided with a pumping chamber having a substantially cylindrical internal peripheral surface and end walls, a rotor located in said pumping chamber, said rotor being rotatable about an axis offset from the axis of the pumping chamber, a pair of radially extending grooves in the rotor, a pair of blades slidably located within said grooves respectively, the opposite ends of each blade cooperating with the peripheral surface of the pumping chamber, an inlet port and an outlet port in communication with said chamber and through which fluid passes as the rotor rotates within the pumping chamber, each blade being divided into two parts and resilient means acting to urge the ends of the two parts of the blade into engagement with the peripheral surface of the pumping chamber, the

two `parts of each blade moving as a single unit Within the respectivel Ygroove as`the`"rotor rotates.

2. The uid pump as claimed in claim 1 in which said resilient means comprises a leaf spring acting between the two parts of each blade.

3. 'Iheiuid` pump as claimed in claim 1 in which the parts of each blade overlap eachV other and aV pair "of leaf springs' are provided'to urge the ends' of the two parts into` engagement with the peripheral surface of the pumping chamber.`

4. A uid pumpy comprising a body provided with a pumping chamber having a substantially cylindrical internal peripheral surface and end walls, a rotor located in ysaid pumping chamber, said rotor being rotatable about an axis" offset from the axis of the pumping chamber, a pair ofi radially `extending grooves in the rotor,a pair of' blades slidably `located within the grooves respectively, theV opposite ends ofeach blade cooperating with the peripheral surface of the pumping chamber, an inlet port and an outlet port in communication with said pumping chamber and through which iluid passes as the rotor rotates within the pumping chamber, each blade being divided into two" parts, the partsA of each blade overlapping each other, a pair of leaf springs acting between the two parts of each blade for urging the ends of the two parts into engagement with the peripheral surface of the pumping chamber and the surfaces of the two parts of each blade between which the leaf springs act being inclined relative to the axis of rotation of the rotor thereby to urge the two parts of each blade in opposite axial directions.

5. The uid pump as claimed in `claim 4 in which one of the faces against which each leaf spring bears is provided with a depression to accommodate the spring and to provide axial location of the spring.

References Cited UNITED STATES PATENTS 732,671 6/ 1903 Andrews 103-136(R3)UX 2,829,603 4/ 1958 Clark 103-136(R3)UX 3,268,157 8/1966 Frenzel 123-8(SS)UX 3,286,699 11/1966 Frenzel 123-8(SS)UX 3,400,691 49/1968 Jones 230-145X 3,447,512 6/ 1969 Winkelmann et al 123--8 DONLEY J. STOCKING, Primary Examiner W. I. KRAUSS, Assistant Examiner 

